1 Nez Perce Tribe, Department of Fisheries Resources Management, 14054 Burr Dr., McCall, Idaho, 83638, USA
✉ Correspondence: Jay Hesse <jayh@nezperce.org>, Ryan N. Kinzer <ryank@nezperce.org>
Updates for the 2024 analysis:
Highlights:
Figure 1.1: Current status of natural-origin Snake River spring/summer Chinook Salmon relative to the quasi-extinction threshold (QET) and Columbia Basin Partnership goals.
Figure 1.2: Estimated slope parameters for natural-origin Snake River spring/summer Chinook Salmon abundance trends indicate an average annual decline of 6% for the last 10-years.
Highlights:
Figure 1.3: Current status of natural-origin Snake River summer steelhead relative to the quasi-extinction threshold (QET) and Columbia Basin Partnership goals.
Figure 1.4: Modeled abundance trends of natural-origin Snake River summer steelhead indicate an annual 11% decline for the last 10-years.
| MPG | Population | Method | First | Last | n | min | max | average | sd |
|---|---|---|---|---|---|---|---|---|---|
| Dry Clearwater | Upper South Fork Clearwater | PIT-tag Observations | 2012 | 2024 | 12 | 75 | 1120 | 408 | 327 |
| Grande Ronde / Imnaha | Big Sheep Creek | PIT-tag Observations | 2011 | 2024 | 13 | 9 | 340 | 77 | 86 |
| Catherine Creek | SGS and Weir Expansions | 1980 | 2024 | 45 | 0 | 1034 | 210 | 229 | |
| PIT-tag Observations | 2015 | 2024 | 9 | 79 | 430 | 183 | 123 | ||
| Grande Ronde River Upper Mainstem | SGS and Weir Expansions | 1980 | 2024 | 45 | 0 | 545 | 89 | 101 | |
| PIT-tag Observations | 2018 | 2024 | 6 | 13 | 93 | 40 | 29 | ||
| Imnaha River Mainstem | SGS and Weir Expansions | 1980 | 2024 | 45 | 139 | 1465 | 515 | 357 | |
| PIT-tag Observations | 2011 | 2024 | 13 | 176 | 1731 | 605 | 437 | ||
| Lookingglass Creek | PIT-tag Observations | 2010 | 2024 | 14 | 33 | 288 | 117 | 84 | |
| Minam River | SGS and Weir Expansions | 1980 | 2024 | 45 | 30 | 1209 | 396 | 252 | |
| Wallowa/Lostine Rivers | SGS and Weir Expansions | 1980 | 2023 | 44 | 37 | 1283 | 409 | 342 | |
| Wenaha River | SGS and Weir Expansions | 1980 | 2024 | 45 | 30 | 767 | 333 | 217 | |
| PIT-tag Observations | 2019 | 2024 | 5 | 118 | 577 | 218 | 201 | ||
| Lower Snake | Asotin Creek | SGS and Weir Expansions | 1984 | 2016 | 33 | 0 | 35 | 7 | 9 |
| PIT-tag Observations | 2010 | 2024 | 14 | 0 | 312 | 53 | 85 | ||
| Tucannon River | SGS and Weir Expansions | 1980 | 2024 | 45 | 4 | 852 | 270 | 232 | |
| Middle Fork Salmon River | Bear Valley Creek | SGS and Weir Expansions | 1980 | 2024 | 45 | 17 | 1315 | 382 | 334 |
| PIT-tag Observations | 2015 | 2024 | 9 | 6 | 1422 | 327 | 443 | ||
| Big Creek | SGS and Weir Expansions | 1980 | 2024 | 45 | 4 | 682 | 181 | 158 | |
| PIT-tag Observations | 2012 | 2024 | 12 | 140 | 1147 | 619 | 338 | ||
| Camas Creek | SGS and Weir Expansions | 1980 | 2024 | 44 | 0 | 294 | 64 | 70 | |
| Chamberlain Creek | SGS and Weir Expansions | 1985 | 2024 | 36 | 0 | 711 | 223 | 179 | |
| Loon Creek | SGS and Weir Expansions | 1980 | 2024 | 44 | 0 | 654 | 85 | 135 | |
| Marsh Creek | SGS and Weir Expansions | 1980 | 2024 | 45 | 0 | 872 | 251 | 222 | |
| Middle Fork Salmon River Lower Mainstem | SGS and Weir Expansions | 1987 | 2024 | 37 | 0 | 63 | 7 | 14 | |
| Middle Fork Salmon River Upper Mainstem | SGS and Weir Expansions | 1995 | 2024 | 30 | 1 | 322 | 84 | 78 | |
| Sulphur Creek | SGS and Weir Expansions | 1980 | 2024 | 45 | 0 | 303 | 68 | 71 | |
| South Fork Salmon River | East Fork South Fork Salmon River | SGS and Weir Expansions | 1987 | 2024 | 38 | 5 | 844 | 251 | 199 |
| PIT-tag Observations | 2010 | 2024 | 14 | 191 | 1223 | 640 | 323 | ||
| Secesh River | SGS and Weir Expansions | 1996 | 2024 | 29 | 139 | 1460 | 555 | 370 | |
| PIT-tag Observations | 2010 | 2024 | 14 | 213 | 1538 | 735 | 395 | ||
| South Fork Salmon River | SGS and Weir Expansions | 1980 | 2024 | 45 | 64 | 1797 | 604 | 404 | |
| PIT-tag Observations | 2010 | 2024 | 14 | 157 | 3583 | 1186 | 1034 | ||
| Upper Salmon River | East Fork Salmon River | SGS and Weir Expansions | 1980 | 2024 | 45 | 7 | 866 | 278 | 242 |
| Lemhi River | SGS and Weir Expansions | 1980 | 2024 | 45 | 10 | 708 | 194 | 163 | |
| PIT-tag Observations | 2010 | 2024 | 14 | 87 | 745 | 324 | 216 | ||
| North Fork Salmon River | SGS and Weir Expansions | 1991 | 2024 | 34 | 2 | 324 | 73 | 73 | |
| PIT-tag Observations | 2016 | 2024 | 7 | 23 | 358 | 106 | 115 | ||
| Pahsimeroi River | SGS and Weir Expansions | 1980 | 2024 | 37 | 0 | 559 | 168 | 142 | |
| Panther Creek | PIT-tag Observations | 2018 | 2024 | 6 | 82 | 371 | 187 | 107 | |
| Salmon River Lower Mainstem | SGS and Weir Expansions | 1980 | 2024 | 45 | 11 | 449 | 120 | 99 | |
| Salmon River Upper Mainstem | SGS and Weir Expansions | 1980 | 2024 | 45 | 23 | 991 | 365 | 242 | |
| Valley Creek | SGS and Weir Expansions | 1980 | 2024 | 45 | 0 | 325 | 102 | 88 | |
| PIT-tag Observations | 2010 | 2024 | 14 | 79 | 675 | 275 | 185 | ||
| Yankee Fork | SGS and Weir Expansions | 1980 | 2024 | 44 | 0 | 358 | 56 | 85 | |
| PIT-tag Observations | 2012 | 2024 | 12 | 28 | 296 | 110 | 99 | ||
| Wet Clearwater | Lochsa River | PIT-tag Observations | 2017 | 2024 | 7 | 135 | 573 | 292 | 149 |
| Lolo Creek | PIT-tag Observations | 2012 | 2024 | 12 | 34 | 312 | 125 | 98 |
| Model Id | Total Parameters | U | Q | R | logLik | AICc | \(\Delta\)AIC |
|---|---|---|---|---|---|---|---|
| 4 | 106 | 7 | 2 | 48 | -1409.39 | 3048.45 | 0.00 |
| 2 | 99 | 1 | 1 | 48 | -1466.43 | 3146.20 | 97.75 |
| 10 | 133 | 34 | 2 | 48 | -1434.48 | 3163.32 | 114.87 |
| 8 | 111 | 7 | 7 | 48 | -1483.20 | 3207.85 | 159.39 |
| 6 | 105 | 7 | 1 | 48 | -1497.10 | 3221.52 | 173.07 |
| 3 | 59 | 7 | 2 | 1 | -1592.07 | 3307.45 | 259.00 |
| 1 | 52 | 1 | 1 | 1 | -1644.39 | 3396.90 | 348.45 |
| 9 | 86 | 34 | 2 | 1 | -1619.06 | 3421.60 | 373.15 |
| 7 | 64 | 7 | 7 | 1 | -1658.74 | 3451.76 | 403.30 |
| 5 | 58 | 7 | 1 | 1 | -1675.38 | 3471.89 | 423.44 |
Figure 3.1: Estimated abundance (natural-log) trends for the seven state processes (xtT) estimated from the best fitting Snake River spring/summer Chinook Salmon model (grey shading represents 95% CI’s).
Figure 3.2: Empirical natural-origin abundance estimates for Snake River spring/summer Chinook Salmon (points) and estimated population trends (ytT) from the best fitting model (line).